With the rapid growth of economy and the steady development of the automobile industry, cars are now extensively used for long-distance travel as well as short-distance transportation. As people's dependence on cars increases, drivers and passengers spend more and more time in cars and become demanding of the comfort and convenience of use of the limited car interior space. In order to provide backseat passengers with a comfortable and refreshing riding experience, it is a trend to mount brackets on the front seats and install an audio/video playing device on each bracket such that the audio/video playing devices are positioned on the backs of the front seats by means of the brackets respectively. Thus, backseat passengers can watch films or listen to music while riding in cars.
Please refer to FIG. 1 for a conventional bracket 10 to be mounted on a seat 13, wherein the bracket 10 is composed essentially of a first plate 11 and two second plates 12. The two ends of the first plate 11 correspond in position to the two headrest supporting rods 131 of the seat 13 and are curved to form first curved portions 111 respectively. Each first curved portion 111 is configured to receive a portion of the corresponding rod 131. In addition, one side of the first plate 11 is centrally provided with an outwardly extending curved post 112. Each second plate 12 has one end curved into a second curved portion 121 for receiving a portion of the corresponding rod 131. The other end of each second plate 12 is formed with a threaded hole 122 through which a screw 15 can pass. To assemble the conventional bracket 10, the first curved portions 111 at both ends of the first plate 11 are brought into contact with one side of the rods 131, and the second curved portion 121 at one end of each second plate 12 is brought in contact with the other side of the corresponding rod 131. Then, two screws 15 are inserted through the threaded holes 122 respectively and fastened to the first plate 11, thereby fastening the two second plates 12 and the first plate 11 together as a single unit. Consequently, the two rods 131 of the seat 13 are clamped by the corresponding first and second curved portions 111, 121 respectively, and the conventional bracket 10 is stably formed on the two rods 131 by the first plate 11 and the two second plates 12. The exposed end of the curved post 112 in the conventional bracket 10 can be engaged in a hole 141 of an audio/video playing device 14 so that the audio/video playing device 14 is secured to the back of the seat 13 via the conventional bracket 10, allowing a backseat passenger to watch films or listen to music via the audio/video playing device 14.
While the conventional bracket 10 described above is widely used due to its simple structure, it has the following drawbacks in use.
First of all, in the conventional bracket 10, the distance between the first curved portions 111 at the two ends of the first plate 11 is fixed and not adjustable. In addition, the second curved portions 121 of the second plates 12 must correspond in position to the first curved portions 111 in order to clamp the rods 131 in conjunction with the corresponding first curved portions 111; hence, the positions of the second curved portions 121 are not adjustable, either. While the positions of the first and second curved portions 111, 121 of the conventional bracket 10 are invariable and cannot be adjusted, the distance between the headrest supporting rods 131 of the seat 13 varies with the model and size of cars. Therefore, manufacturers of the conventional bracket 10 must set up different production lines for producing brackets 10 of different specifications, so as to cope with the various spacings between the headrest supporting rods 131 of seats 13 in different models of cars. As a result, not only is the convenience of use of the conventional bracket 10 substantially restricted, but also the production of brackets 10 of different sizes increases manufacturers' labor and material costs. Moreover, brackets 10 of different specifications incur high storage and transportation costs as well as high production costs.
Secondly, as the positions of the first and second curved portions 111, 121 of the conventional bracket 10 are fixed and not adjustable, once the audio/video playing device 14 is fastened to the conventional bracket 10 and thereby secured on the back of the seat 13, the position of the audio/video playing device 14 is also fixed and cannot be adjusted. Hence, when the position of the seat 13 is adjusted along the forward/backward direction, or when the inclination angle of the seat 13 is changed, the audio/video playing device 14 on the back of the seat 13 is moved or tilted at the same time and leaves the original position. The audio/video playing device 14 may end up too far away from the backseat passenger, or the forward/backward tilt angle or left/right viewing angle of the audio/video playing device 14 may go beyond the passenger's acceptable range, thus making it difficult for the backseat passenger to view the images played by the audio/video playing device 14.
According to the above, the production, storage, and transportation costs of the conventional bracket tend to be high, and the invariable positions of the curved portions of the conventional bracket may hinder the use of the audio/video playing device or other devices installed on the conventional bracket. Therefore, the issue to be addressed by the present invention is to design and make a cantilever bracket to be mounted on a seat, wherein the cantilever bracket includes two cantilevers pivotally connected by a post so that the two cantilevers can be rotated about a rotation axis defined by the post, with a view to adjusting the distance between the fixing seats on the two cantilevers and allowing the fixing seat on each cantilever to be precisely aligned with and mounted around the corresponding headrest supporting rod of the seat. It is intended that the cantilever bracket is applicable to seats with various spacings between the headrest supporting rods and that the position and angle of a device supported by the cantilever bracket can be adjusted simply by rotating the post of the cantilever bracket.